Heat exchanger

ABSTRACT

Disclosed is a heat exchanger capable of exchanging heat between coolant and refrigerant of different kinds in one device and providing an effective heat exchange ratio between the coolant and the refrigerant. The heat exchanger includes a refrigerant flow path having a refrigerant inlet and a refrigerant outlet, and a coolant flow path through which coolant flows to exchange heat with the refrigerant. The coolant flow path includes a first coolant flow path where first coolant flows, and a second coolant flow path where second coolant with a different kind from the first coolant flows. The heat exchanger is partitioned into a first heat exchange section, in which the first coolant exchanges heat with the refrigerant and a second heat exchange section, in which the second coolant exchanges heat with the refrigerant, so that the heat exchange in the first heat exchange section and the heat exchange in the second heat exchange are carried out independently.

FIELD OF THE INVENTION

The present invention relates to a heat exchanger, and moreparticularly, to a water cooled condenser type heat exchanger whichexchanges heat between coolant and refrigerant.

BACKGROUND ART

In general, an air conditioner for a vehicle is a device for cooling orheating the interior of a vehicle by cooling or heating whileintroducing outside air of the vehicle to the interior of the vehicle orcirculating inside air of the vehicle. The air conditioner for thevehicle includes an evaporator disposed inside an air-conditioning casefor a cooling action, a heater core for a heating action, and a modeconverting door for selectively blowing the air cooled by the evaporatoror the air heated by the heater core to each area of the vehicle.

Korean Patent No. 10-1151758 discloses a plate type heat exchanger. FIG.1 is a perspective view of a water cooled heat exchanger according to arelated art, and FIG. 2 is a schematic diagram showing a configurationof the water cooled heat exchanger according to the related art.

Referring to FIGS. 1 and 2, the conventional water cooled heat exchanger9 includes a plurality of plates 1 stacked on one another, a refrigerantinlet 2 for introducing refrigerant therethrough, a refrigerant outlet 3for discharging refrigerant therethrough, a coolant inlet 4 forintroducing coolant therethrough, and a coolant outlet 5 for dischargingcoolant therethrough, which are disposed at one side thereof. The plates1 are stacked on one another to form a refrigerant channel and a coolantchannel therein.

The refrigerant flowing into the heat exchanger through refrigerantinlet 2 flows through the refrigerant channel formed by the plates 1 andis discharged out through the refrigerant outlet 3, so a refrigerantflow path 7 as illustrated in FIG. 2 is formed. Moreover, the coolantflowing into the heat exchanger through the coolant inlet 4 flowsthrough the coolant channel formed by the plates 1 and is discharged outthrough the coolant outlet 5, so a coolant flow path 8 as illustrated inFIG. 2 is formed. The refrigerant of the refrigerant flow path 7 and thecoolant of the coolant flow path 8 exchange heat with each other.

The conventional water cooled heat exchanger 9 performs heat exchangewith refrigerant using waste heat of electronic unit coolant, whichflowed various electronic units through the coolant flow path 8.

However, in case of an electric vehicle which generates lots of wasteheat from coolant of a stack side, the conventional water cooled heatexchanger is disadvantageous in that it may not use the waste heat ofthe coolant of the stack side due to its structure that is not capableof exchanging heat between coolant and refrigerant of different kinds.

Moreover, in order to apply a structure capable of exchanging heatbetween coolant and refrigerant of different kinds, studies forproviding an effective heat exchange ratio between coolant andrefrigerant of different kinds are required.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in view of theabove-mentioned problems occurring in the prior art, and it is an objectof the present invention to provide a heat exchanger which may exchangeheat between coolant and refrigerant of different kinds in one deviceand provide an effective heat exchange ratio between the coolant and therefrigerant of different kinds.

To accomplish the above object, according to the present invention,there is provided a heat exchanger, which includes a refrigerant flowpath having a refrigerant inlet for introducing refrigerant into theheat exchanger and a refrigerant outlet for discharging refrigerant, anda coolant flow path through which coolant flows to exchange heat withthe refrigerant flowing through the refrigerant flow path. The coolantflow path includes a first coolant flow path through which first coolantflows, and a second coolant flow path through which second coolant witha kind different from that of the first coolant flows. The heatexchanger is partitioned into a first heat exchange section, in whichthe first coolant of the first coolant flow path exchanges heat with therefrigerant and a second heat exchange section, in which the secondcoolant of the second coolant flow path exchanges heat with therefrigerant, and the heat exchange in the first heat exchange sectionand the heat exchange in the second heat exchange are carried outindependently.

Moreover, a plurality of plates are stacked on one another to form therefrigerant flow path, the first coolant flow path and the secondcoolant flow path therein, and a partition plate is disposed between theplates to partition the first coolant flow path from the second coolantflow path.

Furthermore, a first coolant inlet for introducing the first coolantinto the heat exchanger and a first coolant outlet for discharging thefirst coolant are disposed at one side in the stacked direction of theplates, and a second coolant inlet for introducing the second coolantinto the heat exchanger and a second coolant outlet for discharging thesecond coolant are disposed at the other side in the stacked directionof the plates. The refrigerant inlet and the refrigerant out aredisposed at the opposite sides in the stacked direction of the plates toform a 2-pass structure.

Additionally, a refrigerant passing hole is formed in the partitionplate so that the refrigerant passed through the first heat exchangesection flows to the second heat exchange section.

Moreover, a ratio of a heat exchange area between the first coolant andthe refrigerant in the first heat exchange section to a heat exchangearea between the second coolant and the refrigerant in the second heatexchange section is controlled according to a temperature differencebetween the first coolant and the second coolant.

Furthermore, the first coolant is a stack coolant, and the secondcoolant is an electronic unit coolant.

Additionally, when temperature of the stack coolant and temperature ofthe electronic unit coolant are equal, a heat exchange area of the stackcoolant is about 65%, and a heat exchange area of the electronic unitcoolant is about 35%.

In addition, if temperature of the stack coolant is 10 degrees higherthan that of the electronic unit coolant, the heat exchange area of thestack coolant and the heat exchange area of the electronic unit coolantis equal to each other.

The heat exchanger according to an exemplary embodiment of the presentinvention may realize a triple heat exchanger by performing heatexchange between coolant and refrigerant of different kinds in a singleheat exchanger, enhance heat exchange efficiency utilizing the coolantof the stack side which is relatively high in waste heat, and control astage ratio of the water cooled condenser according to heat radiationamounts of the stack side and the electronic unit side, therebyobtaining the optimum heat exchange effect.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be apparent from the following detailed description ofthe preferred embodiments of the invention in conjunction with theaccompanying drawings, in which:

FIG. 1 is a perspective view of a water cooled heat exchanger accordingto a related art;

FIG. 2 is a schematic diagram showing a configuration of the watercooled heat exchanger according to the related art;

FIG. 3 is a view showing a heat exchanger according to an exemplaryembodiment of the present invention;

FIG. 4 is a schematic diagram showing a configuration of the heatexchanger according to the exemplary embodiment of the presentinvention;

FIG. 5 is a view showing a plate of the heat exchanger according to theexemplary embodiment of the present invention;

FIG. 6 is a view showing a partition plate of the heat exchangeraccording to the exemplary embodiment of the present invention;

FIGS. 7 and 8 are schematic diagrams respectively showing configurationsof heat exchangers having different heat exchange ratios according tomodifications of the present invention;

FIG. 9 is a configurative view showing a cooling mode of a heat pumpsystem for a vehicle to which the heat exchanger according to theexemplary embodiment of the present invention is applied;

FIG. 10 is a configurative view showing a heating mode of the heat pumpsystem for a vehicle to which the heat exchanger according to theexemplary embodiment of the present invention is applied; and

FIG. 11 is a schematic diagram showing a configuration of a heatexchanger according to a modification of FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a technical configuration of a heat exchanger according toexemplary embodiments of the present invention will be described withreference to the accompanying drawings.

FIG. 3 is a view showing a heat exchanger according to an exemplaryembodiment of the present invention, FIG. 4 is a schematic diagramshowing a configuration of the heat exchanger according to the exemplaryembodiment of the present invention, FIG. 5 is a view showing a plate ofthe heat exchanger according to the exemplary embodiment of the presentinvention, and FIG. 6 is a view showing a partition plate of the heatexchanger according to the exemplary embodiment of the presentinvention.

In the following description, a vertical direction in FIG. 3 is a“stacked direction of plates”.

As shown in FIGS. 3 to 6, a heat exchanger 100 according to an exemplaryembodiment of the present invention is formed by a plurality of plates190 stacked on one another. Each plate 190 has a plate form with apredetermined thickness, and has a plurality of diagonal flow channel toform paths through which refrigerant and coolant flow when the plates190 are stacked on one another.

In other words, the plates 190 are formed in such a way that arefrigerant line 191 and a coolant line 192 are in the neighborhood witheach other, and refrigerant flowing through the refrigerant line 191 andcoolant flowing through the coolant line 192 exchange heat with eachother. However, the heat exchanger is not restricted to theaforementioned form and may be realized in various forms.

The heat exchanger 100 forms a refrigerant flow path 160 having arefrigerant inlet 110 for introducing refrigerant thereinto and arefrigerant outlet 120 for discharging refrigerant. Furthermore, theheat exchanger 100 includes a coolant flow path, and coolant flowingthrough the coolant flow path exchanges heat with the refrigerantflowing through the refrigerant flow path 160.

The coolant flow path includes a first coolant flow path 170 throughwhich first coolant flows, and a second coolant flow path 180 throughwhich second coolant flowing in another area relative to the firstcoolant flows. In this instance, in case of an electric vehicle, thefirst coolant may be coolant of a stack side and the second coolant maybe electronic unit coolant for a motor and various electronic units.Therefore, the heat exchanger according to the exemplary embodiment ofthe present invention may perform heat exchange with refrigerant usingwaste heat of the coolant lines of different two kinds.

The heat exchanger 100 is partitioned into a first heat exchange sectiona, in which the first coolant of the first coolant flow path 170exchanges heat with the refrigerant, and a second heat exchange sectionb, in which the second coolant of the second coolant flow path 180exchanges heat with the refrigerant. The heat exchange between the firstcoolant and the refrigerant in the first heat exchange section a and theheat exchange between the second coolant and the refrigerant in thesecond heat exchange section b are carried out independently.

Through the aforementioned structure, because the coolant and therefrigerant of different kinds exchange heat with each other in thesingle heat exchanger 100, a triple heat exchanger may be realized andmay enhance heat exchange efficiency utilizing the stack side coolantwhich is relatively high in waste heat.

The plates 190 are stacked on one another to form the refrigerant flowpath 160, the first coolant flow path 170, and the second coolant flowpath, which are formed therein. Additionally, a partition plate 150 isdisposed between the plates 190 to partition the first coolant flow path170 from the second coolant flow path 180. The partition plate 150 has arelatively simple structure, such that the heat exchange between thecoolant and the refrigerant may be achieved independently in the firstheat exchange section a and the second heat exchange section b.

Therefore, the refrigerant introduced through the refrigerant inlet 110first exchanges heat with the first coolant in the first heat exchangesection a, and then, flows to the second heat exchange section b tosecond exchange heat with the second coolant in the second heat exchangesection b. After that, the refrigerant is discharged out through therefrigerant outlet 120. Finally, the heat exchange between the coolantand the refrigerant of different kinds is achieved sequentially toprovide effective heat exchange.

In this instance, a refrigerant passing hole 151 is formed in thepartition plate 150 to make the refrigerant flowed the first heatexchange section a flow in the second heat exchange section b. Therefrigerant passing hole 151 makes the refrigerant channel of the firstheat exchange section a communicate with the refrigerant channel of thesecond heat exchange section b.

In the meantime, FIGS. 7 and 8 are schematic diagrams respectivelyshowing configurations of heat exchangers having different heat exchangeratios according to modifications of the present invention.

The heat exchanger 100 controls a ratio of a heat exchange area betweenthe first coolant and the refrigerant in the first heat exchange sectiona to a heat exchange area between the second coolant and the refrigerantin the second heat exchange section b according to a temperaturedifference between the first coolant and the second coolant. A positionof the partition plate 150 in a stacked direction, namely, a ratio oftop and bottom stages of the heat exchanger, is controlled according tothe temperature difference between the first coolant, namely, the stackside coolant, and the second coolant, namely, the electronic unitcoolant, through calculation of a heat radiation amount.

For example, in case of an electric vehicle, such as a pollution-freevehicle, the temperature difference between the stack side coolant andthe electronic unit coolant is formed to be about 15° C., and in thisinstance, a ratio between the first heat exchange section a and thesecond heat exchange section b is formed to be 35:65. Even if there isno difference in coolant temperature, the ratio between the first heatexchange section a and the second heat exchange section b may be formedto be 65:35.

In other words, when temperature of the stack side coolant andtemperature of the electronic unit coolant are equal, a heat exchangearea of the stack side coolant is about 65%, and a heat exchange area ofthe electronic unit coolant is about 35%. Moreover, if the coolanttemperature of the stack side coolant is 10 degrees higher than thecoolant temperature of the electronic unit coolant, the heat exchangearea of the stack side coolant and the heat exchange area of theelectronic unit coolant may be formed to be equal to each other.

FIG. 7 illustrates that the first heat exchange section a is larger thanthe second heat exchange section b and the heat exchange area betweenthe first coolant and the refrigerant is larger than the heat exchangearea between the second coolant and the refrigerant, and FIG. 8illustrates that the first heat exchange section a is smaller than thesecond heat exchange section b and the heat exchange area between thefirst coolant and the refrigerant is smaller than the heat exchange areabetween the second coolant and the refrigerant.

As described above, the heat exchanger according to the exemplaryembodiment of the present invention controls the stage ratio of thewater cooled condenser according to the heat radiation amounts of thestack side and the electronic unit side so as to obtain the optimum heatexchange effect.

FIG. 9 is a configurative view showing a cooling mode of a heat pumpsystem for a vehicle to which the heat exchanger according to theexemplary embodiment of the present invention is applied, and FIG. 10 isa configurative view showing a heating mode of the heat pump system fora vehicle to which the heat exchanger according to the exemplaryembodiment of the present invention is applied.

Referring to FIGS. 9 and 10, a heat pump system for a vehicle accordingto an exemplary embodiment of the present invention includes arefrigerant circulation line 313, a compressor 301, an exterior heatexchanger 311, an orifice 327, an evaporator 303, a coolant circulationline 315, a heat exchanger 100, namely, a coolant-refrigerant heatexchanger, and a heater core 319.

The compressor 301 is disposed on the refrigerant circulation line 313to compress and discharge refrigerant. An accumulator 309 is mounted atthe upstream side of the compressor 301 in a refrigerant flow direction.The accumulator 309 separates gas-phase refrigerant and liquid-phaserefrigerant from refrigerant, which will be supplied to the compressor301, and supplies only the gas-phase refrigerant to the compressor 301.The exterior heat exchanger 311 is mounted outside of anair-conditioning case 323 and exchanges heat between the refrigerantcirculating the refrigerant circulation line 313 and outdoor air.

The orifice 327 is to throttle the refrigerant flowing through therefrigerant circulation line 313, and is arranged between the exteriorheat exchanger 311 and the evaporator 303. The evaporator 303 is mountedinside the air-conditioning case 323 to exchange heat between inside airof the air-conditioning case 323 and the refrigerant flowing through therefrigerant circulation line 313. The coolant circulation line 315 is apath through which the coolant passing a stack 325, and the coolantflowing through the coolant circulation line 315 exchanges heat with therefrigerant flowing through the refrigerant circulation line 313. Awater pump 317 for forcedly circulating the coolant is disposed on thecoolant circulation line 315.

The heat exchanger 100 may be a coolant-refrigerant chiller, and has thesame structure as illustrated in FIGS. 3 and 4. The heat exchanger 100exchanges heat between the refrigerant flowing through the refrigerantcirculation line 313 and the coolant flowing through the coolantcirculation line 315. The heater core 319 is mounted on the coolantcirculation line 315 and is arranged inside the air-conditioning case323 to exchange heat between inside air of the air-conditioning case 323and the coolant flowing through the coolant circulation line 315. Theevaporator 303 and the heater core 319 are sequentially disposed insidethe air-conditioning case 323 in the air flow direction, and atemperature-adjusting door 321 is disposed between the evaporator 303and the heater core 319.

Referring to FIG. 9, in a cooling mode, the refrigerant discharged fromthe compressor 301 passes a three-way valve, and exchanges heat withoutdoor air in the exterior heat exchanger 311. After that, therefrigerant passes the orifice 327, exchanges heat with inside air ofthe air-conditioning case 323 while passing through the evaporator 303,and then, circulates the compressor 301 after passing through thethree-way valve and the accumulator 309. At the same time, the coolantflowing through the coolant circulation line 315 circulates thecoolant-refrigerant heat exchanger 100 after passing the heater core319, and the coolant circulating the heat exchanger 100 exchanges heatwith the refrigerant circulating through the refrigerant circulationline 313. The coolant passed the coolant-refrigerant heat exchanger 100circulates the heater core 319 again after passing the stack 325.

Moreover, referring to FIG. 10, in a heating mode, the refrigerantdischarged from the compressor 301 exchanges heat with the inside air ofthe air-conditioning case 323 while passing through the evaporator 303after passing the three-way valve, and then, passes through the orifice327, a two-way valve 305, and the coolant-refrigerant heat exchanger 100in order. After that, the refrigerant passes through the accumulator309, and then, circulates the compressor 301. At the same time, thecoolant flowing through the coolant circulation line 315 circulates thecoolant-refrigerant heat exchanger 100 after passing the heater core319, and the coolant circulating the coolant-refrigerant heat exchanger100 exchanges heat with the refrigerant circulating through therefrigerant circulation line 313. The coolant passed thecoolant-refrigerant heat exchanger 100 circulates the heater core 319again after passing the stack 325. In the heating mode, refrigerant heatis radiated from the evaporator 303 to act as heat for heating, and isused as evaporation energy of refrigerant by recovering waste heat ofthe stack 325 through the coolant-refrigerant heat exchanger 100.

The heat exchanger 100 is configured so that the refrigerant flowingthrough the refrigerant flow path 160 first exchanges heat with thecoolant, which is higher in temperature, of the first coolant and thesecond coolant flowing through the coolant flow path. As an example,when temperature of the stack side coolant is about 60° C. andtemperature of the electronic unit coolant is about 40° C., therefrigerant flows through the refrigerant flow path 160 in the directionillustrated in FIG. 4. The refrigerant absorbs heat by first exchangingheat with the first coolant with temperature of about 60° C., and then,absorbs heat by exchanging heat with the second coolant with temperatureof about 40° C. The refrigerant lowers temperature of the refrigerant byfinally exchanging heat with the coolant with lower temperature in theheat exchanger 100 so as to enhance cooling efficiency.

FIG. 11 is a schematic diagram showing a configuration of a heatexchanger according to a modification of FIG. 4. Referring to FIG. 11,the heat exchanger 100 includes a refrigerant flow path 160 and acoolant flow path, and coolant flowing through the coolant flow pathexchanges heat with refrigerant flowing through the refrigerant flowpath 160. The coolant flow path includes a first coolant flow path 170through which first coolant flows and a second coolant flow path 180through which second coolant with a kind different from the firstcoolant flows. The heat exchanger 100 is partitioned into a first heatexchange section a, in which the first coolant of the first coolant flowpath 170 exchanges heat with the refrigerant, and a second heat exchangesection b, in which the second coolant of the second coolant flow path180 exchanges heat with the refrigerant.

The heat exchanger 100 includes a bypass channel 184. The bypass channel184 is formed at the second coolant flow path 180, and bypasses thecoolant introduced into the heat exchanger 100 to prevent the coolantfrom flowing into the heat exchanger 100. The bypass channel 184 isbranched at the upstream side of an inlet of the second coolant flowpath 180 and is connected to the downstream side of an outlet. A valve185 may be disposed at the branch portion to selectively control thecoolant to flow toward the heat exchanger or bypass the coolant.

In other words, referring to FIGS. 9 and 10, in the cooling mode, therefrigerant of the heat exchanger 100 radiates heat, exchanges heat withthe first coolant, and then, exchanges heat with the second coolant.Moreover, in the heating mode, the refrigerant of the heat exchanger 100absorbs heat and the coolant of the second coolant flow path 180 isbypassed, so that the refrigerant exchanges heat only with the firstcoolant. In the heat exchanger 100, the coolant flowing through thesecond coolant flow path 180 is bypassed and does not exchange heat withthe refrigerant so as to prevent deterioration in heating efficiency.

In the meantime, in the aforementioned exemplary embodiment, it isdescribed that, in case of the electric vehicle, the first coolant maybe stack side coolant and the second coolant may be electronic unitcoolant for a motor and various electronic units, but the presentinvention is not limited thereto. The first coolant may be coolant whichflows different heat sources, such as a stack, a battery and others,according to kinds of vehicles, such as electric vehicles, hybridvehicles and so on.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various modifications andequivalents may be made without deviating from the spirit or scope ofthe invention. Therefore, it would be understood that the technical andprotective scope of the present invention shall be defined by thetechnical idea as defined by the following claims and the equivalences.

1. A heat exchanger, which includes a refrigerant flow path having arefrigerant inlet for introducing refrigerant into the heat exchangerand a refrigerant outlet for discharging refrigerant, and a coolant flowpath through which coolant flows to exchange heat with the refrigerantflowing through the refrigerant flow path, wherein the coolant flow pathincludes a first coolant flow path through which first coolant flows,and a second coolant flow path through which second coolant flowing inanother place relative to the first coolant flows, and wherein the heatexchanger is partitioned into a first heat exchange section, in whichthe first coolant of the first coolant flow path exchanges heat with therefrigerant and a second heat exchange section, in which the secondcoolant of the second coolant flow path exchanges heat with therefrigerant, and the heat exchange in the first heat exchange sectionand the heat exchange in the second heat exchange are carried outindependently.
 2. The heat exchanger according to claim 1, wherein aplurality of plates are stacked on one another to form the refrigerantflow path, the first coolant flow path and the second coolant flow paththerein, and wherein a partition plate is disposed between the plates topartition the first coolant flow path from the second coolant flow path.3. The heat exchanger according to claim 2, wherein a first coolantinlet for introducing the first coolant into the heat exchanger and afirst coolant outlet for discharging the first coolant are disposed atone side in the stacked direction of the plates, and a second coolantinlet for introducing the second coolant into the heat exchanger and asecond coolant outlet for discharging the second coolant are disposed atthe other side in the stacked direction of the plates, and wherein therefrigerant inlet and the refrigerant out are disposed at the oppositesides in the stacked direction of the plates to form a 2-pass structure.4. The heat exchanger according to claim 3, wherein a refrigerantpassing hole is formed in the partition plate so that the refrigerantpassed through the first heat exchange section flows to the second heatexchange section.
 5. The heat exchanger according to claim 1, wherein aratio of a heat exchange area between the first coolant and therefrigerant in the first heat exchange section to a heat exchange areabetween the second coolant and the refrigerant in the second heatexchange section is controlled according to a temperature differencebetween the first coolant and the second coolant.
 6. The heat exchangeraccording to claim 1, wherein the first coolant is a stack coolant andthe second coolant is an electronic unit coolant.
 7. The heat exchangeraccording to claim 6, wherein, when temperature of the stack coolant andtemperature of the electronic unit coolant are equal, a heat exchangearea of the stack coolant is about 65%, and a heat exchange area of theelectronic unit coolant is about 35%.
 8. The heat exchanger according toclaim 6, wherein, when temperature of the stack coolant is 10 degreeshigher than that of the electronic unit coolant, the heat exchange areaof the stack coolant and the heat exchange area of the electronic unitcoolant is equal to each other.
 9. The heat exchanger according to claim1, wherein the refrigerant flowing through the refrigerant flow pathfirst exchanges heat with the coolant, which is higher in temperature,of the first coolant and the second coolant.
 10. The heat exchangeraccording to claim 1, wherein a bypass channel is disposed on at leastone of the first coolant flow path and the second coolant flow path tobypass the coolant.
 11. The heat exchanger according to claim 10,wherein, in a cooling mode that the refrigerant radiates heat, therefrigerant exchanges heat with the second coolant after exchanging heatwith the first coolant, and wherein, in a heating mode that therefrigerant absorbs heat, the coolant of the second coolant flow pathexchanges heat only with the first coolant after being bypassed.
 12. Aheat exchanger comprising: a first heat exchange section for exchangingheat between first coolant and refrigerant; a second heat exchangesection for exchanging heat between second coolant, which flows inanother place relative to the first coolant, and the refrigerant, thesecond heat exchange section being partitioned from the first heatexchange section to exchange heat independently; a first coolant flowpath formed in the first heat exchange section; a second coolant flowpath formed in the second heat exchange section; and a refrigerant flowpath formed to penetrate through the first heat exchange section and thesecond heat exchange section.